World No.1 Novak Djokovic hit back at criticism from Nick Kyrgios on Sunday, saying he has little respect for the Australian firebrand off the court.
Kyrgios, a long-time critic of Djokovic, labelled him a "tool" on social media last month after the Serb sent Australian Open organisers a list of requests from players seeking to have quarantine restrictions eased during their mandatory two-week isolation.
Djokovic said Kyrgios was good for tennis, and a talent that could beat any player on his day, but he was not someone the Serb admired away from the game.
"My respect goes to him for the tennis he's playing. I think he's a very talented guy," Djokovic says. "He's got a big game and proven that he has a quality to beat any player really in the world in the past.
"Off the court, I don't have much respect for him, to be honest. That's where I'll close it.
"I really don't have any further comments for him, his own comments for me or anything else he's trying to do."
Defending champion Djokovic starts his bid for a record-extending ninth Australian Open title, as well as an 18th Grand Slam crown, on Monday against unseeded Frenchman Jeremy Chardy in the evening session at Rod Laver Arena.
He was in fine form during the ATP Cup, though Serbia's title defence ended in the quarter-finals with a doubles defeat to Germany.
Players have noted the blue hardcourts of Melbourne Park are quicker than usual and while Djokovic felt that would favour the big servers he had full confidence in his return game, arguably the best in tennis.
"Comparing to say, five, six years ago, it's a lot quicker than it used to be," he says.
"So it obviously favours big servers. You have to adapt your game. I think with my return, I've managed to win a lot of matches against big servers on these kind of courts.
"I improved my serve, I think, also alongside Goran Ivanisevic, one of the biggest servers ever, he improved a lot the method of my serve.
"I think in these kind of conditions you really need to have a complete game in order to go all the way.
"I've managed somehow to always adapt very well to Rod Laver Arena. Whatever the speed or conditions, somehow that court has always been my favourite court."